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2,495 results on '"Kaushik A. Kumar"'

5. Energy Efficient Skyrmion based Oscillator on Thermocoupled Nanotrack

Author

Raj, Ravish Kumar, Bindal, Namita, and Kaushik, Brajesh Kumar

Subjects
Physics - Applied Physics
Abstract

The magnetic skyrmion-based spin transfer nano-oscillators (STNO) are the potential candidates for next-generation microwave signal generator and has gained popularity due to their performance, integrability and compatibility with existing CMOS technology. However, these devices suffer from the Joule heating problem that neglects their non-volatility advantage in spintronic devices. Therefore, it is necessary to investigate the alternative driving mechanisms for the development of energy-efficient skyrmion based nano-oscillators. In this paper, a skyrmion-based nano-oscillator has been designed that utilizes thermal power to drive skyrmion on a thermocoupled nanotrack. The thermocoupled nanotrack is designed in such a way that both the upper and lower nanotracks have different values of damping constants and a temperature difference is maintained between the extreme ends, in order to create a temperature gradient in the two nanotracks. By employing this technique, skyrmion is able to exhibit the periodic motion on the nanotrack with the maximum achievable frequency of 2.5GHz without any external stimuli. Moreover, the proposed device offers low thermal energy consumption of 0.84fJ/oscillation. Hence, this work provides the pathway for the development of energy-efficient future spintronic devices.

Published
2023

6. Introduction

Author

Chindaliya, Sakshi, Thomas, Ashika, Mohan, Deepanshu, Kaushik, Arun Kumar, Mohan, Deepanshu, editor, Chindaliya, Sakshi, editor, and Kaushik, Arun Kumar, editor

Published
2024
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7. Reflections

Author

Thomas, Ashika, Chindaliya, Sakshi, Mohan, Deepanshu, Kaushik, Arun Kumar, Mohan, Deepanshu, editor, Chindaliya, Sakshi, editor, and Kaushik, Arun Kumar, editor

Published
2024
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8. [Feminist] Ethnography in Crisis

Author

Chindaliya, Sakshi, Thomas, Ashika, Mohan, Deepanshu, Kaushik, Arun Kumar, Mohan, Deepanshu, editor, Chindaliya, Sakshi, editor, and Kaushik, Arun Kumar, editor

Published
2024
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15. Skyrmion-mediated Nonvolatile Ternary Memory

Author

Rajib, Md Mahadi, Bindal, Namita, Raj, Ravish Kumar, Kaushik, Brajesh Kumar, and Atulasimha, Jayasimha

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Multistate memory systems have the ability to store and process more data in the same physical space as binary memory systems, making them a potential alternative to existing binary memory systems. In the past, it has been demonstrated that voltage-controlled magnetic anisotropy (VCMA) based writing is highly energy-efficient compared to other writing methods used in non-volatile nano-magnetic binary memory systems. In this study, we introduce a new, VCMA-based and skyrmion-mediated non-volatile ternary memory system using a perpendicular magnetic tunnel junction (p-MTJ) in the presence of room temperature thermal perturbation. We have also shown that ternary states {-1, 0, +1} can be implemented with three magnetoresistance values obtained from a p-MTJ corresponding to ferromagnetic up, down, and skyrmion state, with 99% switching probability in the presence of room temperature thermal noise in an energy-efficient way, requiring ~3 fJ energy on an average for each switching operation. Additionally, we show that our proposed ternary memory demonstrates an improvement in area and energy by at least 2X and ~60X respectively, compared to state-of-the-art spin-transfer torque (STT)-based non-volatile magnetic multistate memories. Furthermore, these three states can be potentially utilized for energy-efficient, high-density in-memory quantized deep neural network implementation.

Published
2023

16. Roadmap for Unconventional Computing with Nanotechnology

Author

Finocchio, Giovanni, Incorvia, Jean Anne C., Friedman, Joseph S., Yang, Qu, Giordano, Anna, Grollier, Julie, Yang, Hyunsoo, Ciubotaru, Florin, Chumak, Andrii, Naeemi, Azad J., Cotofana, Sorin D., Tomasello, Riccardo, Panagopoulos, Christos, Carpentieri, Mario, Lin, Peng, Pan, Gang, Yang, J. Joshua, Todri-Sanial, Aida, Boschetto, Gabriele, Makasheva, Kremena, Sangwan, Vinod K., Trivedi, Amit Ranjan, Hersam, Mark C., Camsari, Kerem Y., McMahon, Peter L., Datta, Supriyo, Koiller, Belita, Aguilar, Gabriel H., Temporão, Guilherme P., Rodrigues, Davi R., Sunada, Satoshi, Everschor-Sitte, Karin, Tatsumura, Kosuke, Goto, Hayato, Puliafito, Vito, Åkerman, Johan, Takesue, Hiroki, Di Ventra, Massimiliano, Pershin, Yuriy V., Mukhopadhyay, Saibal, Roy, Kaushik, Wang, I-Ting, Kang, Wang, Zhu, Yao, Kaushik, Brajesh Kumar, Hasler, Jennifer, Ganguly, Samiran, Ghosh, Avik W., Levy, William, Roychowdhury, Vwani, and Bandyopadhyay, Supriyo

Subjects
Computer Science - Emerging Technologies, Physics - Applied Physics
Abstract

In the "Beyond Moore's Law" era, with increasing edge intelligence, domain-specific computing embracing unconventional approaches will become increasingly prevalent. At the same time, adopting a variety of nanotechnologies will offer benefits in energy cost, computational speed, reduced footprint, cyber resilience, and processing power. The time is ripe for a roadmap for unconventional computing with nanotechnologies to guide future research, and this collection aims to fill that need. The authors provide a comprehensive roadmap for neuromorphic computing using electron spins, memristive devices, two-dimensional nanomaterials, nanomagnets, and various dynamical systems. They also address other paradigms such as Ising machines, Bayesian inference engines, probabilistic computing with p-bits, processing in memory, quantum memories and algorithms, computing with skyrmions and spin waves, and brain-inspired computing for incremental learning and problem-solving in severely resource-constrained environments. These approaches have advantages over traditional Boolean computing based on von Neumann architecture. As the computational requirements for artificial intelligence grow 50 times faster than Moore's Law for electronics, more unconventional approaches to computing and signal processing will appear on the horizon, and this roadmap will help identify future needs and challenges. In a very fertile field, experts in the field aim to present some of the dominant and most promising technologies for unconventional computing that will be around for some time to come. Within a holistic approach, the goal is to provide pathways for solidifying the field and guiding future impactful discoveries., Comment: 80 pages accepted in Nano Futures

Published
2023
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20. Antiferromagnetic skyrmion dynamics in stepped geometry for various applications.

Author

Saini, Shipra, Verma, Ravi Shankar, and Kaushik, Brajesh Kumar

Subjects
PARTICLE spin, SKYRMIONS, MAGNETIC fields, SPINTRONICS, ANISOTROPY
Abstract

Antiferromagnetic skyrmions are tiny particle like spin textures, topologically more stable, having low depinning current density. They are potential candidate for spintronics devices owing to their robustness toward external magnetic field perturbations. Precise control of the skyrmion motion is essential for applications such as racetrack memories, multistate memories, and neuromorphic computing devices. However, in conventional nanotracks, these particles could not be stabilized due to inter-skyrmion repulsion. Hence, in the case of domain wall-based racetracks and multi-state memory devices, extra notches or similar geometric confinements are included within the nanotrack. Here, we show that a stepped nanotrack geometry is one possible solution for controlling the skyrmion dynamics that can be further employed in racetrack memory, multistate memory, and leaky integrate-and-fire neuron devices. Compared to the domain wall depinning current density of ∼1011–1012 A/m2, only ∼106 A/m2 is required for skyrmions. Additionally, we observe that the modified skyrmion racetracks with stepped geometry can mimic the functionality of the biological neuron, including the leaky behavior, eliminating the need for an anisotropy gradient, Dzyaloshinskii–Moriya interaction gradient, or thermal gradient, which is required for the case of domain wall nanotrack. The current density required to drive the skyrmions on this modified nanotrack is ∼1010 A/m2. The effects of defects and edge roughness due to the fabrication process are also studied. [ABSTRACT FROM AUTHOR]

Published
2024
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23. Antiferromagnetic Skyrmion based Energy-Efficient Leaky Integrate and Fire Neuron Device

Author

Bindal, Namita, Raj, Ravish Kumar, Rajib, Md Mahadi, Atulasimha, Jayasimha, and Kaushik, Brajesh Kumar

Subjects
Physics - Applied Physics
Abstract

The development of energy-efficient neuromorphic hardware using spintronic devices based on antiferromagnetic (AFM) skyrmion motion on nanotracks has gained considerable interest. Owing to its properties such as robustness against external magnetic fields, negligible stray fields, and zero net topological charge, AFM skyrmions follow straight trajectories that prevent their annihilation at nanoscale racetrack edges. This makes the AFM skyrmions a more favorable candidate over the ferromagnetic (FM) skyrmion for future spintronic applications. This work proposes an AFM skyrmion-based neuron device exhibiting the leaky-integrate-fire (LIF) functionality by exploiting thermal gradient or alternatively perpendicular magnetic anisotropy (PMA) gradient in the nanotrack for leaky behavior by moving the skyrmion in the direction to minimize the system energy. Furthermore, it is shown that the AFM skyrmion couples efficiently to the soft ferromagnetic layer of a magnetic tunnel junction enabling efficient read-out of the skyrmion. The maximum change of 9.2% in tunnel magnetoresistance (TMR) is estimated for detecting the AFM skyrmion. Moreover, the proposed neuron device has the energy dissipation of 4.32 fJ per LIF operation thus, paving the path for developing energy-efficient devices in antiferromagnetic spintronics for neuromorphic computing.

Published
2022

30. Controlled in vivo intrinsic detrimental effect of d-Limonene channelized by influential proximal interaction through apoptosis and steatosis in embryonic zebrafish (Danio rerio)

Author

Choudhury, Anmol, Lenka, Sudakshya S., Gupta, Abha, Mandal, Deepa, Sinha, Adrija, Saha, Utsa, Naser, Shaikh Sheeran, Singh, Dibyangshee, Simnani, Faizan Zarreen, Ghosh, Aishee, Kumari, Shalini, Kirti, Apoorv, Parija, Tithi, Chauhan, Raghuraj Singh, Kaushik, Nagendra Kumar, Suar, Mrutyunjay, and Verma, Suresh K.

Published
2024
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